babel-polyfill - error Error: only one instance of babel-polyfill is allowed

I’m submitting a bug report

Webpack Version: 1.14.0

Babel Core Version: 6.23.1

Babel Loader Version: 6.3.2

Please tell us about your environment: Windows 10

Current behavior: I try to use babel-polyfill for ie11 with webpack

entry: {
    app: ['babel-polyfill','./src/main.js']
}

After ie11 reconize Array.includes but in some pages i have error in other browsers like Firefox error Error: only one instance of babel-polyfill is allowed

[lipemat]

There was another 3rd party library which included the babel-polyfill in their bundle. To fix this I had to remove the babel-polyfill from the entry in webpack.config and add a conditional require to the top of my index.js which is the entry point.

Before webpack.config:

module.exports = {
	entry : [
		'babel-polyfill', './src/index'
	]
}

After webpack.config:

module.exports = {
	entry : [
		'./src/index'
	]
}

Added to the top of ./src/index.js:

if (!global._babelPolyfill) {
	require('babel-polyfill');
}

Now everything works without issue.

[swarajban]

I was also seeing this error, but after checking my html, I was also including my bundled JS twice. Fixed by updating my HTML to ensure I only include my bundle once